Key Nutrients Help Keep Your Mind Agile

The Chicago Tribune What if mental decline did not have to be a natural consequence of aging? What if part of the secret to staying sharp lies in the foods we eat? Emerging evidence suggests that getting enough of certain nutrients - namely iron, zinc and B vitamins - may help stave off cognitive decline seen with aging, possibly even Alzheimer's and dementia.

Cognitive function, which encompasses many aspects of brain power including memory, reasoning, perception, concentration and learning ability, is a precious possession, especially as we age. Preserving your brainpower may be easier than you think. "We're learning that if you feed your brain the right nutrients, it will work harder for you throughout life," said Dayle Hayes, a dietitian and author in Billings, Mont. It is well known that iron deficiency impairs brain development and learning in children. "The adult brain may also be affected by iron deficiency," said Mary Kretsch, research physiologist with the Department of Agriculture's Western Human Nutrition Research Center in Davis, Calif.

Recent studies conducted by Kretsch and her colleagues found a decline in concentration and short-term memory associated with low iron intakes in women who were dieting. In men, as iron and zinc levels in the body declined, decreases in attention span were measured. A surprising and significant finding also became evident: The ability to concentrate declines prior to the onset of iron and zinc deficiency. "This is a real concern," Kretsch said, "especially for people wanting optimal mental productivity, since the effects of iron and zinc deficiency occur earlier than we would have predicted."

There is growing evidence that getting enough B vitamins can prevent, slow or reverse deterioration in memory and other mental capacities. B vitamins - particularly folic acid (or folate), vitamin B6 and vitamin B12 - are known to play a role in the production of important brain chemicals required for cognition and other brain functions. The Normative Aging study, an ongoing study of aging in middle-aged to elderly men by the Massachusetts Veterans Epidemiology Research and Information Center, found that low blood levels of vitamin B12 and folic acid were associated with changes in spatial ability, measured by the ability to copy a three-dimensional figure. Higher blood levels of vitamin B6 were linked to better performance on tests of memory.

The homocysteine link Researchers also are examining the effects of B vitamins from another angle. It seems that individuals with Alzheimer's and dementia have higher levels of an amino acid called homocysteine in their blood. B vitamins help to break down homocysteine in the body. Increased homocysteine levels have also been linked to a greater risk for heart disease and stroke. "There is an amazing correlation," said Katherine Tucker, associate professor at the Tufts University School of Nutrition Science and Policy. "When B-vitamin intake is low, homocysteine levels rise, and we find a decline in brain function." Over a lifetime, Tucker and others speculate that this may influence risk for developing Alzheimer's and other types of dementia in later years.

Food for thought Experts agree that in most instances wise food choices can prevent nutrient deficiencies. The one exception to this is vitamin B12 for older adults. "Even if older adults manage to consume enough B12, which is found bound to the protein in meat and dairy products," Tucker said, "they often suffer from an age-related decrease in stomach acid that prevents them from fully absorbing vitamin B12." This is why adults age 50 and older are advised to take a vitamin B12 supplement or get this vitamin from fortified foods, such as fortified cereals. Iron and zinc are available in - and best absorbed from - meat, poultry and seafood. Fortified cereals, whole grains and dried beans are also good sources. "Hands down, the best source of both iron and zinc is lean beef," Hayes said. The iron and zinc in plant foods is not as easily absorbed. If you're over 50, Tucker recommends a multivitamin and mineral supplement formulated for seniors to get a balance of B vitamins, in addition to eating minimally processed foods.